While $(NuGetPackageVersion) replaces the "+" with "-" and allows nuget pack to succeed, if you use -IncludeReferencedProjects nuget because the AssemblyInformationalVersionAttribute value is invalid.
What might be nice is to allow (opt-in, to avoid breaking compat) semver 1.0 versions. We were able to work around this by hooking in our own target, but others may run into this as well.